Veteran FBI agents say FBI Director James Comey has permanently damaged the bureau’s reputation for uncompromising investigations with his “cowardly” whitewash of former Secretary of State Hillary Clinton’s mishandling of classified information using an unauthorized private email server.

Feeling the heat from congressional critics, Comey last week argued that the case was investigated by career FBI agents, “So if I blew it, they blew it, too.”

But agents say Comey tied investigators’ hands by agreeing to unheard-of ground rules and other demands by the lawyers for Clinton and her aides that limited their investigation.

“In my 25 years with the bureau, I never had any ground rules in my interviews,” said retired agent Dennis V. Hughes, the first chief of the FBI’s computer investigations unit.

Instead of going to prosecutors and insisting on using grand jury leverage to compel testimony and seize evidence, Comey allowed immunity for several key witnesses, including potential targets.

The immunity agreements came with outrageous side deals, including preventing agents from searching for any documents on a Dell laptop owned by former Clinton chief of staff Cheryl Mills generated after Jan. 31, 2015, when she communicated with the server administrator who destroyed subpoenaed emails.

Comey also agreed to have Mills’ laptop destroyed after the restricted search, denying Congress the chance to look at it and making the FBI an accomplice to the destruction of evidence.

Comey’s immunized witnesses nonetheless suffered chronic lapses in memory, made unsubstantiated claims of attorney-client privilege upon tougher questioning and at least two gave demonstrably false statements. And yet Comey indulged it all.

What’s more, Comey cut a deal to give Clinton a “voluntary” witness interview on a major holiday, and even let her ex-chief of staff sit in on the interview as a lawyer, even though she, too, was under investigation.

Clinton’s interview, the culmination of a yearlong investigation, lasted just 3½ hours. Despite some 40 bouts of amnesia, she wasn’t called back for questioning; and three days later, Comey cleared her of criminal wrongdoing.

“The FBI has politicized itself, and its reputation will suffer for a long time,” Hughes said. “I hold Director Comey responsible.”

The accommodations afforded Clinton and her aides are “unprecedented,” Biasello added, “which is another way of saying this outcome was by design.” He called Comey’s decision not to seek charges “cowardly.”

“Each month for 27 years, I received oral and computer admonishments concerning the proper protocol for handling top secret and other classified material, and was informed of the harsh penalties, to include prosecution and incarceration,” for mishandling such material, he pointed out. “Had myself or my colleagues engaged in behavior of the magnitude of Hillary Clinton, as described by Comey, we would be serving time in Leavenworth.”

Former FBI official I.C. Smith knows a thing or two about Clinton corruption. After working at FBI headquarters as a section chief in the National Security Division, he retired as special agent in charge of the Little Rock, Ark., field office, where he investigated top Clinton fundraisers for public corruption and even Chinese espionage.

“FBI agents upset with Comey’s decision have every reason to feel that way,” Smith said. “Clearly there was a different standard applied to Clinton.”

“I have no doubt resourceful prosecutors and FBI agents could have come up with some charge that she would have been subject to prosecution,” the 25-year veteran added. “What she did is absolutely abhorrent for anyone who has access to classified information.”

Smith said Congress should subpoena the case’s agents to testify about the direction they received from Comey and their supervisors: “It would be interesting to see what the results would be if those involved with the investigation were questioned under oath.”

Comey made the 25 agents who worked on the case sign nondisclosure agreements. But others say morale has sunk inside the bureau.

“The director is giving the bureau a bad rap with all the gaps in the investigation,” one agent in the Washington field office said. “There’s a perception that the FBI has been politicized and let down the country.”

Comey has turned a once-proud institution known for its independence into one that bows to election pressure, hands out political immunity to candidates and effectively pardons their co-conspirators. He’s turned the FBI into the Federal Bureau of Immunity and lost the trust and respect of not only his agents but the country at large. He ought to step down.